Overview

Selby, G. and D.C. Glenn-Lewin. 1990. An ecological study of the plant/butterfly associations and their response to management, at the Prairie Coteau Scientific and Natural Area (SNA), Pipestone County, Minnesota. Final report submitted to the Minnesota Department of Natural Resources. 31+ pp.

Overview:

The objectives of this study were to: 1) examine the occurrence and distributional patterns of rare butterflies in relation to plant community associations and environmental factors such as soils, topography, aspect, and available moisture; 2) examine the relationship between the phenology of important nectar and food plants, and the flight patterns for the prairie-obligate butterfly species; 3) examine the response of the rare butterflies and their associated nectar and food sources to management practices such as fire and grazing; 4) continue to test the population monitoring methodology at Prairie Coteau and apply it to other sites; and 5) document the butterfly and plant species which occur at each study site.

Hesperia dacotae (Skinner) was the focus of the study, but other prairie-obligate species for which distribution and behavioral data were collected include Atrytone arogos iowa (Scudder), Atrytonopsis hianna hianna (Scudder), Clossiana selene (Denis & Schiffermuller), Coenonympha tullia inornata, Glaucopsyche lygdamus (Doubleday), Hesperia leonardus pawnee (Harris), Hesperia ottoe (W.H. Edwards), Lycaeides melissa melissa, Oarisma poweshiek (Parker), Polites mystic, and Speyeria idalia (Drury). The primary purpose of fieldwork at the other sites was to document the presence of rare butterflies at those sites, and to set up transects for population monitoring at Hole-in-the-Mountain preserve. Species lists were compiled for each site, and the number and distribution of selected prairie-obligate species were recorded.

Species were targeted for population monitoring in each of 3 flight periods: 1) late May to late Jun. - A.h. hianna, C.T. inornata, L.m. melissa; 2) late Jun. to late Jul. - A.a. iowa, H. dacotae, H. ottoe, O. poweshiek, and S. idalia; and 3) late Aug. through Sept. - H.l. pawnee, and S. idalia. Species lists were compiled and for the prairie-obligate species, the number of individuals observed and their approx. location were recorded. The survey sites included Pipestone National Monument, Pipestone, MN; Blue Mound State Park, Rock County, MN; and Chanarambie Creek Site, Murray County, MN.

A total of 43 butterfly species were recorded from Prairie Coteau in 1988 and 1989. New species documented in 1990 included Basilarchia archippus archippus (Viceroy), Poanes massasoit (Mulberry Marsh Skipper), and Vanessa virginiensis (American Painted Lady). This brings the total number of species documented at the site to 46. Sightings for H. ottoe were still very low, with only 3 individuals (1 unconfirmed) observed. With the exception of H. ottoe, there continue to be good populations of prairie-obligate butterflies at Prairie Coteau. Significant occurrences of prairie-obligate butterflies were found at each of the other sites that were surveyed.